This invention relates to an alternator apparatus for powering a capacitor discharge ignition system for internal combustion engines and auxiliary electrical equipment and particularly to such apparatus for a two cylinder engine designed for application to outboard motor units and the like.
Capacitor discharge ignition systems have been developed for application in internal combustion engines and have particularly been employed in connection with propulsion devices such as outboard motors, snowmobiles, motorcycles and similar vehicles.
Generally, the capacitor discharge ignition systems employ one or more firing capacitors. Suitable control switch means such as controlled rectifiers connect the capacitor or capacitors to the spark plugs for discharging of the capacitor and firing of the engine. The alternator is constructed and connected for charging the capacitor and for generating the triggering pulses for firing the controlled rectifiers.
The ignition system, particularly for smaller outboard engines and the like, is advantageously powered from an engine driven alternator unit. Space limitation generally requires a relatively small, compact, lightweight construction. The alternator unit may be conveniently incorporated into the flywheel structure of the engine. The flywheel is formed as a cup-shaped member secured to the engine shaft with a rotor means secured within the skirt. A stator coil assembly is mounted in fixed relation to the engine with appropriate coils coupled to the rotor means. The rotor means includes suitable permanent magnet members with spaced flux reversal points or portions to provide appropriate coupling to the stator assembly for generating appropriate charging power to the ignition capacitor and appropriate trigger signals for discharging thereof at the proper time.
In one system for a two cylinder engine, a pair of ignition capacitors are connected to be alternately charged from a charging coil unit and alternately discharged from a separate trigger coil unit.
In many engine driven propulsion devices, auxiliary electrical devices such as lights, starters, a battery and the like are provided. An alternator unit is preferably constructed and connected to provide a rectified voltage output for charging of the battery or an A.C. voltage output for operating lights. Although separate alternator units may be provided, a single integrated assembly is desirable, particularly where severe space limitations are encountered, such as in small outboard motor units.
Although compact alternator units have been suggested, the location of the various functioning coils within a common compact and integrated construction tends to create cross-coupling between the several signal generating systems and in particular may cause improper or undesired ignition. Although such systems do, therefore, provide improved engine operation, a high degree of reliability and maximum efficiency of operation is often not obtained, particularly in the small, compact constructions.